Conventionally, there are known a parallel beam method in which a specimen is irradiated with a parallel X-ray beam and a diffracted X-ray is detected with a two-dimensional X-ray detector, and a focusing method (so-called a Bragg Brentano optical system (B-B optical system)) in which a diverging beam is applied to a specimen and a diffracted X-ray concentrated on a focal circle is detected with a zero-dimensional or one-dimensional x-ray detector. When these methods are used to perform measurements, each optical system needs to be configured, and separate apparatuses are basically used. To overcome this problem, there is proposed an apparatus that can perform measurements based on both the parallel beam method and the focusing method (for example, see patent document 1).
There is also proposed an apparatus that collects X-rays emanated from an X-ray source on one spot on a specimen with a Johansson crystal so as to collect and apply an X-ray beam on a narrow region on the specimen, and that measures X-ray diffraction from the spot on the specimen (for example, see patent document 2).